There is an optical device including: a lens; and an optical component transmitting light to the lens or receiving light that has passed through the lens. The technology related to such an optical device is disclosed in Japanese Unexamined Patent Application Publication No. 2007-201939.
To modularize such a lens and an optical component, it is conceivable to provide the lens and the optical component within a single case and to air-seal the case. However, when the case is air-sealed, the case might be deformed before and after air-sealing. This deformation might cause the lens to be displaced from its desirable position.